PCT publication no. WO2013/179137 discloses various medical implants. Some of these implants comprise an un-deployed and a deployed state. In the un-deployed state, the implant is substantially linear, and in the deployed state the implant assumes a shape directed at providing a medically beneficial function. The implants are typically made of super elastic alloy, such as nitinol. The implants disclosed in the patent documents mentioned above include embolic protection devices for preventing brain stroke and pulmonary embolism, body vessel occlusion devices, stents, and delivery platforms for therapeutic agents (for example, drugs and ionizing radiation).
The implants are typically delivered via a thin needle and a pusher/plunger configured to be slidably received within the lumen of the needle. Initially the implant is disposed in its un-deployed, substantially linear state near the distal end of the needle's lumen, and the pusher is disposed within the lumen proximally to the proximal end of the implant. In operation, the needle is directed by an operator to a suitable implantation site, such as, for example, an artery or a vein. Once the desired needle position is achieved, the pusher is used to push the implant out of the distal end of the needle. As the implant is exteriorized it assumes its functional deployed shape inside the target vessel. Following complete exteriorization of the implant from the needle, the needle and the pusher are withdrawn from the patient's body, and the implantation procedure is complete.
Since the lumen of the delivery needle is typically of very small diameter (e.g., ranging from 0.05 to 0.5 mm), as well as the pusher diameter being equally correspondingly small (e.g., also ranging from 0.05 to 0.5 mm), the pusher may buckle under the push force required for pushing the implant out of the needle.
Since the operator typically uses ultrasound imaging to guide the implantation procedure, the operator typically holds an ultrasound probe in one hand and the delivery system in the other hand. As a result, the operator may need another person in manipulating the delivery system. For example, the operator may need the help of another person in exteriorizing the implant by pushing the pusher. This complicates the delivery procedure.
Moreover, it may be crucial that the implant be sized accordingly with respect to at least one of its dimensions to specific sizes according to the desired functionality. A sizing mistake may prevent the implant from assuming a correct functional shape inside the vessel.